Project Summary Sexually transmitted infections (STIs) are at a record high in the United States, and STI risk is an increasingly critical and costly health problem for American childbearing women. STIs and alcohol/drug use are interrelated and common morbidities that have direct and indirect relationships to health and functioning over the longer term for mother and fetus. Because of the intersection between substance use and STIs, and because both are associated with poor health outcomes, there is an urgent need to intervene with pregnant women in order to jointly address risky sexual behaviors and substance use during this vulnerable time period. While pregnancy has been recognized as a window of opportunity in which to intervene, very few interventions exist that target both of these risks, and virtually none are tailored to pregnant women's specific context and unique concerns. The objective of this R01 study is to fill this critical gap by building upon our promising R21 findings to test whether the innovative, theory-driven ?Health Check-up for Expectant Moms? (HCEM) reduces STI, alcohol use and drug use risk more than a time and information matched control condition in pregnant women seeking prenatal care. This research addresses priorities in line with NICHD's mission and Scientific Vision to advance the health of women: (1) promoting research to develop interventions that influence a range of behaviors and outcomes, (2) developing and enhancing personalized treatment that targets pregnant women, and (3) decreasing the potential for poor birth outcomes among women at greatest risk. We propose a two- group, randomized controlled trial in which a racially diverse sample of 250 high-risk (at risk for STIs and alcohol/drug use) pregnant women attending prenatal care in high-volume primary care clinics will be assigned to either (a) a computer-delivered, single-session brief intervention plus two booster sessions (within one month after the intervention) consistent with motivational interviewing and informed by the Information- Motivation-Behavior (IMB) model, the HCEM, or (b) a computer-delivered control condition. Computer- delivered follow-up assessments will occur at 8 and 24-weeks antenatally, and at 6-weeks postpartum, extending outcomes to the postpartum period. Specific Aim 1 is to test the hypothesis that HCEM, compared to an attention, time and information matched control condition, will reduce unprotected sexual occasions, alcohol use and drug use among at-risk pregnant women during pregnancy at 2 and 6-months follow up. Specific Aim 2 is to test the hypothesis that HCEM, compared to control, will reduce STIs and alcohol/drug use at 6-weeks postpartum and will result in better birth outcomes. An economic evaluation of the costs of the intervention will occur to guide future implementation and dissemination. Specific Aim 3 is to explore direct and indirect effects in the above hypotheses. Results of this program of research are expected to inform the development of integrated STI and alcohol/drug use interventions that are cost-effective, high-reaching and widely disseminable during pregnancy with benefits for mother and infant extending impact to the postpartum period.